Comic relief: Laughter is a natural painkiller

This is no laughing matter (or maybe it is): A small British study has found that laughter can increase your tolerance of pain. It seems that cracking up in the company of other people releases endorphins, the same feel-good brain chemicals triggered while exercising.

Laughter is helpful when you're hurting because it's hard work for the body. A hearty, sustained laugh is a good workout for muscles in the chest and lungs, and this can trigger the release of endorphins to mask the pain, says Robin Dunbar, PhD, a professor of evolutionary psychology at Oxford University, who led the study. When endorphin levels increase, a person's pain threshold rise, he explains.

For the study, published in the Proceedings of the Royal Society B, scientists ran a series of six different experiments in the lab and one in a real-world setting, during live stage performances at the Edinburgh Fringe Festival. Many of the tests were done in small groups because other research has shown that laughter is 30 times more likely to occur in a social situation than when you're alone.

In some studies, half of the volunteers watched a comedy video -- ranging from episodes of "South Park" and "Friends" to "Mr. Bean" and "The Simpsons" -- while the others viewed a documentary on dull stuff like golf instruction, pet training, or a nature show.

Each participant's individual pain threshold was tested before and after watching the videos, using such pain-inducing techniques as an increasingly tighter blood pressure cuff around the upper arm or a frozen wine cooler sleeve placed on the forearm and held there until the person couldn't take it any longer. Pain tolerance was considered a proxy measure of endorphin levels.

Researchers also recorded the amount of time participants spent laughing. But polite titters wouldn't cut it; only relaxed social laughter that stretched smile muscles in the face counted.

Pain tolerance was shown to be higher in men and women who watched funny videos, but they stayed the same or were lower in those who didn't. Scientists were also able to tease out that a person's ability to handle more pain was due to the laughter itself and not just because it put someone in a better mood.

Laughter is definitely some of the best medicine for pain, says Dunbar. It seems that endorphins tune up the immune system, so triggering their release through laughter helps you recover from disease and allows the body to resist infection, he explains

Would some comic relief help those suffering from chronic pain? Presumably, the more you engage in social events that involve laughter, you'll be better able to bear chronic pain, Dunbar says.

"No doubt the pharmaceutical companies won't like it, but laughter would save on hospital bills," he points out.